/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.zookeeper;

import jline.Completor;

import java.util.List;

class JLineZNodeCompletor implements Completor
{
    private ZooKeeper zk;

    public JLineZNodeCompletor(ZooKeeper zk)
    {
        this.zk = zk;
    }

    @SuppressWarnings("unchecked")
    public int complete(String buffer, int cursor, List candidates)
    {
        // Guarantee that the final token is the one we're expanding
        buffer = buffer.substring(0, cursor);
        String token = "";
        if (!buffer.endsWith(" "))
        {
            String[] tokens = buffer.split(" ");
            if (tokens.length != 0)
            {
                token = tokens[tokens.length - 1];
            }
        }

        if (token.startsWith("/"))
        {
            return completeZNode(buffer, token, candidates);
        }
        return completeCommand(buffer, token, candidates);
    }

    private int completeCommand(String buffer, String token,
                                List<String> candidates)
    {
        for (String cmd : ZooKeeperMain.getCommands())
        {
            if (cmd.startsWith(token))
            {
                candidates.add(cmd);
            }
        }
        return buffer.lastIndexOf(" ") + 1;
    }

    private int completeZNode(String buffer, String token,
                              List<String> candidates)
    {
        String path = token;
        int idx = path.lastIndexOf("/") + 1;
        String prefix = path.substring(idx);
        try
        {
            // Only the root path can end in a /, so strip it off every other prefix
            String dir = idx == 1 ? "/" : path.substring(0, idx - 1);
            List<String> children = zk.getChildren(dir, false);
            for (String child : children)
            {
                if (child.startsWith(prefix))
                {
                    candidates.add(child);
                }
            }
        } catch (InterruptedException e)
        {
            return 0;
        } catch (KeeperException e)
        {
            return 0;
        }
        return candidates.size() == 0 ? buffer.length() : buffer.lastIndexOf("/") + 1;
    }
}
